es6问题，为什么无法得到action.subreddit

Question

let b2 = (avc) => avc
let a1 = b2('世界');

console.log("a1==" + a1)

let action = function selectSubreddit(subreddit) {
  return {
    type: 'SELECT_SUBREDDIT',
    subreddit
  }
}

selectSubreddit("ub");

console.log("action.subreddit==" + action.subreddit)

Answer 1

let b2 = (avc) => avc
let a1 = b2('世界');

console.log("a1==" + a1)

function selectSubreddit(subreddit) {
  return {
    type: 'SELECT_SUBREDDIT',
    subreddit
  }
}

let action = selectSubreddit("ub");

console.log("action.subreddit==" + action.subreddit)

Answer 2

let action = function selectSubreddit(subreddit) {
  return {
    type: 'SELECT_SUBREDDIT',
    subreddit
  }
}

这个用法是什么意思？

Answer 3

let action = function (subreddit) {
return {

type: 'SELECT_SUBREDDIT',
subreddit

}
}

函数声明和函数表达式不要一起用呀。